This Special Issue reprint focuses on the exquisite and cognitive plant behaviors emerging from their complex relationship with a constantly changing environment, including the vast network of communications that link plants to other plants and different organisms. More and more evidence has demonstrated that plants are not merely stimulus-response reactive objects, responding passively to the external environment. On the contrary, they have their own plant-specific agency, and their interactions with the variable environment involves directed and intentional actions that are regulated by sophisticated processes of sensing and signaling. Such interactions form communication networks with neighboring plants that also interfere positively or negatively in the way each individual thrives.

Research is showing that plants are in constant and lively discourse--they communicate, signaling to remote organs within an individual, eavesdropping on neighboring individuals, and exchanging information with other organisms ranging from other plants to microbes to animals. Plants lack central nervous systems, and the mechanisms coordinating plant sensing, behavior, and communication are quite different from the systems that accomplish similar tasks in animals. But they are no less impressive from an evolutionary perspective. In "Plant Communication, "Karban puts an ear to the ground to reveal the world of plant communication and information sensing. He reveals their sensory capabilities, the learning capacity of plants, sensory signaling and communication, the different responses to pollinators and predators, and the mechanisms that undergird this impressive behavioral repertoire. The book shows that plants are hardly the inanimate organisms limited by their stationary existence."

Since the concept of allelopathy was introduced almost 100 years ago, research has led to an understanding that plants are involved in complex communicative interactions. They use a battery of different signals that convey plant-relevant information within plant individuals as well as between plants of the same species or different species. The 13 chapters of this volume discuss all these topics from an ecological perspective. Communication between plants allows them to share physiological and ecological information relevant for their survival and ?tness. It is obvious that in these very early days of ecological plant communication research we are illuminating only the ‘tip of iceberg’ of the communicative nature of higher plants. Nevertheless, knowledge on the identity and informative value of volatiles used by plants for communication is increasing with breath-taking speed. Among the most spectacular examples are sit- tions where plant emitters warn neighbours about a danger, increasing their innate immunity, or when herbivore-attacked plants attract the enemies of the herbivores (‘cry for help’ and ‘plant bodyguards’ concepts). It is becoming obvious that plants use not only volatile signals but also diverse water soluble molecules, in the case of plant roots, to safeguard their evolutionary success and accomplish self/non-self kin rec- nition. Importantly, as with all the examples of biocommunication, irrespective of whether signals and signs are transmitted via physical or chemical pathways, plant communication is a rule-governed and sign-mediated process.

Since the concept of allelopathy was introduced almost 100 years ago, research has led to an understanding that plants are involved in complex communicative interactions. They use a battery of different signals that convey plant-relevant information within plant individuals as well as between plants of the same species or different species. The 13 chapters of this volume discuss all these topics from an ecological perspective. Communication between plants allows them to share physiological and ecological information relevant for their survival and ?tness. It is obvious that in these very early days of ecological plant communication research we are illuminating only the ‘tip of iceberg’ of the communicative nature of higher plants. Nevertheless, knowledge on the identity and informative value of volatiles used by plants for communication is increasing with breath-taking speed. Among the most spectacular examples are sit- tions where plant emitters warn neighbours about a danger, increasing their innate immunity, or when herbivore-attacked plants attract the enemies of the herbivores (‘cry for help’ and ‘plant bodyguards’ concepts). It is becoming obvious that plants use not only volatile signals but also diverse water soluble molecules, in the case of plant roots, to safeguard their evolutionary success and accomplish self/non-self kin rec- nition. Importantly, as with all the examples of biocommunication, irrespective of whether signals and signs are transmitted via physical or chemical pathways, plant communication is a rule-governed and sign-mediated process.

Plant neurobiology is a newly emerging field of plant sciences. It covers signalling and communication at all levels of biological organization – from molecules up to ecological communities. In this book, plants are presented as intelligent and social organisms with complex forms of communication and information processing. Authors from diverse backgrounds such as molecular and cellular biology, electrophysiology, as well as ecology treat the most important aspects of plant communication, including the plant immune system, abilities of plants to recognize self, signal transduction, receptors, plant neurotransmitters and plant neurophysiology. Further, plants are able to recognize the identity of herbivores and organize the defence responses accordingly. The similarities in animal and plant neuronal/immune systems are discussed too. All these hidden aspects of plant life and behaviour will stimulate further intense investigations in order to understand the communicative plants in their whole complexity.

Our image of plants is changing dramatically away from passive entities merely subject to environmental forces and organisms that are designed solely for the accumulation of photosynthate. Plants are revealing themselves to be dynamic and highly sensitive organisms that actively and competitively forage for limited resources, both above and below ground, organisms that accurately gauge their circumstances, use sophisticated cost-benefit analysis, and take clear actions to mitigate and control diverse environmental threats. Moreover, plants are also capable of complex recognition of self and non-self and are territorial in behavior. They are as sophisticated in behavior as animals but their potential has been masked because it operates on time scales many orders of magnitude less than those of animals. Plants are sessile organisms. As such, the only alternative to a rapidly changing environment is rapid adaptation. This book will focus on all these new and exciting aspects of plant biology.